1. Field of the Invention
The present invention is directed to Ethernet communication systems and, more particularly, to Ethernet physical layer devices.
2. Related Art
Ethernet is a widely used technology in local area networks (“LAN”) and other computer networks. The Institute for Electrical and Electronics Engineers (“IEEE”) has developed standards for Ethernet communication systems. See, for example, IEEE 802.3, incorporated herein by reference in its entirety. The IEEE 802.3 standards have been adopted by the International Organization for Standardization (“ISO”), making the IEEE 802.3 standards worldwide standards.
In an Ethernet network, a computer utilizes an Ethernet transceiver to transmit and receive signals between the computer and another device. The transceiver typically interfaces with the other device via a physical link medium, such as copper or fiber.
An Ethernet transceiver typically includes a media access controller (“MAC”) that interfaces with applications running on the computer. Alternatively, an Ethernet module can include a switch or an optical module. An Ethernet transceiver also includes a physical layer device, or “PHY” that interfaces between the MAC/switch and a physical link media, such as a copper link media. PHYs typically interface with physical link media using data streams. PHYs typically interface with MACs/switches using packet-based interfaces. PHYs have to operate in the same mode as their corresponding MACs. Of interest here are a serial gigabit media independent interface (“SGMII”) mode and a gigabit interface converter (“GBIC”) mode.
What is needed is a PHY that supports both SGMII and GBIC modes of operation, and that interfaces with copper link media. What is also needed is a PHY that detects a mode of operation of a MAC/switch and that switches between SGMII and GBIC modes, without software intervention, to match the MAC/switch mode of operation.